Siloxane resin-based anti-reflective coating composition having high wet etch rate

ABSTRACT

Herein we disclose a composition, comprising a siloxane resin having the formula (HSiO 3/2 ) a . (SiO 4/2 ) b (HSiX 3/2 ) c (SiX 4/2 ) d , wherein each X is independently —O—, —OH, or —O—(CH 2 ) m —Z n , wherein each m is independently an integer from 1 to about 5, Z is an 5 aromatic moiety, and each n is independently an integer from 1 to about 6; 0&lt;a&lt;1, 0&lt;b&lt;1, 0&lt;c&lt;1, 0&lt;d&lt;1, and a+b+c+d=1. We also disclose methods for preparing the siloxane resin composition and a method of preparing an anti-reflective coating on a substrate, wherein the anti-reflective coating is derived from the siloxane resin composition.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of antireflectivecoatings for use in fabricating semiconductor devices. Moreparticularly, it relates to antireflective coatings formed from dyedsiloxane resins.

Photolithography is a known technique in the art of semiconductorfabrication. In a typical photolithography process, a semiconductorwafer is coated with a barrier layer, aka. an anti-reflective coating(ARC) layer. Thereafter, a photoresist layer is coated on the ARC layer.The photoresist/ARC/semiconductor wafer is then brought into proximityto a source of electromagnetic radiation (EM), typically ultravioletlight (UV) having a wavelength from about 150 nm to about 300 nm, and amask is interposed between the EM source and thephotoresist/ARC/semiconductor wafer. The mask is generally opaque to thewavelength of EM used, but has transparent regions defining a desiredpattern to be imparted to the photoresist layer.

When the source emits EM, the mask allows exposure of EM to particularand user-defined regions of the photoresist layer. Both positivephotoresists and negative photoresists are known. In a positivephotoresist, the regions of photoresist exposed to UV, as well as theregions of the ARC layer thereunder, will be sacrificed duringsubsequent developing steps. In a negative photoresist, the regions ofphotoresist which are not exposed to UV, as well as the regions of theARC layer thereunder, will be sacrificed during subsequent developingsteps.

Regardless of the details of the photolithography process, an ARC layerdesirably has several properties. One property is a relatively highextinction coefficient, i.e., a relatively strong ability to absorb thewavelength of EM used, rather than reflect the EM up to the photoresistlayer. A second property is a relatively low resistance to liquidstripping agents, such as diluted hydrofluoric acid, in order to morequickly and easily be removed after photolithography and minimize theextent of damage by a stripping agent to the low-k dielectric materialon a wafer.

SUMMARY OF THE INVENTION

In one embodiment, the present invention relates to a composition,comprising a dyed siloxane resin having the formula(HSiO_(3/2))_(a)(SiO_(4/2))_(b)(HSiX_(3/2))_(c)(Si_(4/2))_(d), whereineach X is independently —O—, —OH, or —O—(CH₂)_(m)—Z_(n), provided atleast one X is —O—(CH₂)_(m)—Z_(n), wherein Z_(n) is a polycyclicaromatic hydrocarbon moiety comprising n aromatic rings, each m isindependently an integer from 1 to about 5, and each n is independentlyan integer from 1 to about 6; 0<a<1, 0<b<1, 0<c<1, 0<d<1, and a+b+c+d=1.

In another embodiment, the present invention relates to a method forpreparing a siloxane resin composition, comprising reacting atrialkoxysilane, a tetraalkoxysilane, and water in the presence of ahydrolysis catalyst, to form a siloxane resin having HSiO_(3/2),SiO_(4/2), (HSiX_(3/2)) and SiX′_(4/2) units, wherein X′ isindependently —O— or —OH, and having substantially no silicon-carbonbonds; and reacting the siloxane resin with a compound having theformula HO—(CH₂)_(m)—Z_(n), wherein each m is independently an integerfrom 1 to about 5, and each n is independently an integer from 1 toabout 6, to form the siloxane resin composition. The method can beperformed as sequential steps or a single step.

In a further embodiment, the present invention relates to a method ofpreparing an anti-reflective coating on a substrate, comprising coatinga composition onto a substrate to form a coated substrate, wherein thecomposition comprises a siloxane resin having the formula(HSiO_(3/2))_(a)(SiO_(4/2))_(b)(HSiX_(3/2))_(c)(SiX_(4/2))_(d), whereineach X is independently —O—, —OH, or —O—(CH₂)_(m)—Z_(n), provided atleast one X is —O—(CH₂)_(m)—Z_(n), wherein Z_(n) is a polycyclicaromatic hydrocarbon moiety comprising n aromatic rings, wherein each mis independently an integer from 1 to about 5, and each n isindependently an integer from 1 to about 6; 0<a<1, 0<b<1, 0<c<1, 0<d<1,and a+b+c+d=1; and curing the coated substrate, to form theanti-reflective coating on the substrate.

In yet another embodiment, the present invention relates to asemiconductor wafer, prepared according to the above method of preparingan anti-reflective coating on a substrate.

The dyed siloxane resin compositions of the present invention provideARC layers having relatively high extinction coefficients for UV havingwavelengths from about 150 nm to about 300 nm, and a relatively lowresistance to liquid stripping agents such as dilute hydrofluoric acid,a.k.a. a high wet etch rate.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In one embodiment, the present invention relates to a composition,comprising a siloxane resin having the formula:(HSiO3/2)_(a)(SiO_(4/2))_(b)(HSiX_(3/2))_(c)(SiX_(4/2))_(d),

wherein each X is independently —O—, —OH, or —O—(CH₂)_(m)—Z_(n),provided at least one X is —O—(CH₂)_(m)—Z_(n), wherein Z_(n) is apolycyclic aromatic hydrocarbon moiety comprising n aromatic rings,wherein each m is independently an integer from 1 to about 5, and each nis independently an integer from 1 to about 6; 0<a<1, 0<b<1, 0<c<1,0<d<1, and a+b+c+d=1.

The HSiO_(3/2) and SiO_(4/2) units are well known to the skilledartisan. Typically, a small proportion of “SiO_(4/2)” units comprisesome one or more silanol (Si—OH) moieties, that is, some SiO_(4/2) unitscan have formulas such as HO—SiO_(3/2), (HO)₂SiO2/2, etc. and remainwithin the scope of the term “SiO_(4/2) units.”

The HSiX_(3/2) units, as hereby defined, refer to units comprising oneor more of the following structures. For convenience, only one of thethree non-H silicon valences is shown in each of the followingstructures; the two valences not shown can be selected from any of thefollowing structures. In one structure, wherein an X is —O—; theHSiX_(3/2) unit will comprise Si—O—, by which is meant that the oxygenof the X moiety is bonded to a silicon atom of another unit of theresin. In another structure, wherein an X is —OH, the HSiX_(3/2) unitwill comprise Si—OH, which can be referred to as a silanol moiety. In athird structure, wherein an X is —O—(CH₂)_(m)—Z_(n), the HSiX_(3/2) unitwill comprise Si—O—(CH₂)_(m)—Z_(n.)

The SiX_(4/2) units, as hereby defined, refer to units comprising one ormore of the following structures. For convenience, only one of the foursilicon valences is shown in each of the following structures; the threevalences not shown can be selected from any of the following structures,provided at least one X is —O—(CH₂)_(m)—Z_(n). In one structure, whereinan X is —O—, the SiX_(4/2) unit will comprise Si—O—, by which is meantthat the oxygen of the X moiety is bonded to a silicon atom of anotherunit of the resin. In another structure, wherein an X is —OH, theSiX_(4/2) unit will comprise Si—OH, which can be referred to as asilanol moiety. In a third structure, wherein an X is—O—(CH₂)_(m)—Z_(n), the SiX_(4/2) unit will compriseSi—O—(CH₂)_(m)—Z_(n).

The term “Z_(n)” as used herein, refers to a substituted or anunsubstituted polycyclic aromatic hydrocarbon moiety comprising naromatic rings, wherein n is from 1 to about 6; e.g., phenyl,naphthalenyl, phenanthrenyl, anthracenyl, chrysenyl, pyrenyl, orcoronenyl moieties, among others. In one embodiment, X is independently—O—, —OH, or —O—(CH₂)—Z₃, provided at least one X is —O—(CH₂)_(m)—Z₃. Inone embodiment, —(CH₂)_(m)—Z₃ is a 9-anthracene methylene moiety (i.e.,m=1).

The proportions of the various units of the resin can vary, providedthat the mole fractions of each are between 0 and 1 (i.e., 0<a<1, 0<b<1,0<c<1, 0<d<1) and the sum of the mole fractions is 1. In one embodiment,the mole fractions have the values 0.3≦a≦0.7, 0.3≦b≦0.7,and 0<(c+d)≦0.6.

The composition can further comprise an organic solvent. Exemplarysolvents include, but are not limited to, 2-ethoxyethanol,1-methoxy-2-propanol, and propylene glycol monoether, among others. Thecomposition can comprise from about 80% to about 99% solvent by weight.The composition can further comprise additional components useful incoating applications or in other applications for which the compositioncan be used. In one embodiment, the composition further comprises water.The composition can comprise from about 0% to about 15% water by weight.In another embodiment, the composition further comprises a non-volatileacid such as sulfuric acid (H₂SO₄), which may facilitate the curing ofthe thin film at a moderately low temperature. The composition cancomprise from about 0 ppm (parts per million of total composition byweight) to about 500 ppm acid.

In one embodiment, the present invention relates to a method forpreparing a siloxane resin composition, comprising:

(i) reacting a trialkoxysilane, a tetraalkoxysilane, and water in thepresence of a hydrolysis catalyst, to form a first siloxane resin havingHSiO_(3/2), SiO_(4/2), HSiX′_(3/2), and Six′_(4/2)units, wherein X′ isindependently —O— or —OH, and having substantially no silicon-carbonbonds; and

(ii) reacting the first siloxane resin with a compound having theformula HO—(CH₂)_(m)—Z_(n), wherein each m is independently an integerfrom 1 to about 5, and each n is independently an integer from 1 toabout 6, to form the siloxane resin composition.

In reacting step (i), a trialkoxysilane, a tetraalkoxysilane, and watercan be reacted in the presence of a hydrolysis catalyst, to form thefirst siloxane resin.

A “trialkoxysilane,” as used herein, is a compound having the formulaHSiR₃, wherein each R is independently a C₁-C₆ alkoxy moiety. Exemplaryalkoxy moieties include, but are not limited to, methoxy, n-propoxy, andn-butoxy moieties, among others. In one embodiment, the trialkoxysilaneis triethoxysilane (HSi(OCH₂CH₃)₃).

A “tetraalkoxysilane,” as used herein, is a compound having the formulaSiR₄, wherein each R is independently a C₁-C₆ alkoxy moiety as describedabove. In one embodiment, the tetraalkoxysilane is tetraethoxysilane(Si(OCH₂CH₃)₄).

The weight ratio of trialkoxysilane:tetraalkoxysilane can be from 0:1 to1:0. The higher the weight ratio of trialkoxysilane:tetraalkoxysilane,the greater the mole fraction ratio of HSiO_(3/2) to SiO_(4/2) units inthe first siloxane resin. The trialkoxysilane and the tetraalkoxysilanemay be referred to collectively as “alkoxysilanes.”

The amount of water in the reaction (i) can be from about 2 molar partsper molar part of alkoxysilanes to about 15 molar parts per molar partof alkoxysilanes. In one embodiment, the amount of water is from about 3molar parts per molar part of alkoxysilanes to about 5 molar parts permolar part of alkoxysilanes. Though not to be bound by theory, theinclusion of water in the reaction (i) is believed to lead to theformation of silanol (Si—OH) moieties. Some, but typically not all, ofthe silanol moieties are believed to undergo condensation reactions withother silanol moieties (Si—OH+HO—Si) to form silica linkages (Si—O—Si)and water (H₂O). The remaining silanol moieties remain condensed andthus are potentially reactive with alcohol moieties.

Generally, alkoxysilanes are either not soluble in water or sparinglysoluble in water. In light of this, the reaction (i) can be performed inan organic solution, by which is meant, the alkoxysilanes can bedissolved in an organic solvent in which they are either relativelyhighly soluble or miscible. In one embodiment, the organic solvent is2-ethoxyethanol. In another embodiment, the organic solvent is1-methoxy-2-propanol. An organic solvent can be present in any amountsufficient to dissolve the other components of the reaction mixture. Inone embodiment, the weight ratio of organic solvent:alkoxysilanes is atleast about 10:1. In another embodiment, the organic solvent is presentfrom about 70% to about 99% by total weight of the reaction mixture.

Alternatively, the reaction (i) can be performed in suspension inaqueous solution, or in emulsion in aqueous solution, wherein in thelatter technique an appropriate surfactant or cosolvent can be used torender the alkoxysilanes at least relatively highly soluble in aqueoussolution.

The temperature of the reacting step (i) is not crucial, provided it isa temperature at which the first siloxane resin can form.

The duration of the reacting step (i) is not crucial, provided it issufficiently long for the reaction to go to a desired level ofcompleteness.

The reacting step (i) can be performed in the presence of a catalystwhich promotes the reaction (a “hydrolysis catalyst”). The catalyst canbe a base or an acid. In one embodiment, reacting step (i) can beperformed in the presence of a mineral acid. Useful mineral acidsinclude, but are not limited to, HCl, HF, HBr, HNO₃, and H₂SO₄, amongothers. In one embodiment, the catalyst is HCl. The benefit of HCl orother volatile acids is that a volatile acid can be easily removed fromthe composition by stripping after the reaction (i) is completed. Theamount of catalyst may depend on its nature. For example, when thecatalyst is HCl, 0.05% to 1% of HCl by total weight of the reactionmixture can be used.

The first siloxane resin will have substantially no silicon-carbonbonds, i.e., less than about 5 mol % of all atoms bonded to siliconatoms will be carbon. However, some few silicon-carbon bonds may form asa result of the reaction, such as through low levels of side reactionsor by the presence-of reactant contaminants having silicon-carbon bonds.

In reacting step (ii), the first siloxane resin can be reacted with acompound having the formula HO—(CH₂)_(m)—Z_(n), wherein each m isindependently an integer from 1 to about 5, and each n is independentlyan integer from 1 to about 6, to form the siloxane resin composition.

Compounds having the formula HO—(CH₂)_(m)—Z_(n) are known in the art andfrequently have dye properties, by which is meant they have relativelyhigh extinction coefficients at one or more wavelengths ofelectromagnetic (EM) radiation, such as wavelengths within theultraviolet region of the EM spectrum. A relatively high extinctioncoefficient leads to a relatively high absorbance and a relatively lowtransmission of EM radiation at the one or more wavelengths. In oneembodiment, the compound having the formula HO—(CH₂)_(m)—Z_(n) is9-anthracenemethanol. In another embodiment, the compound ishydroxybenzyl alcohol. In yet another embodiment, the compound isbenzyloxybenzyl alcohol.

Reacting step (ii) can be performed by adding the compound having theformula HO—(CH₂)_(m)—Z_(n) to the solution, suspension, or emulsioncontaining the first siloxane resin. Optionally, compounds such as wateror a non-volatile mineral acid, such as H2SO4, can be added before orafter the reacting step (ii). In one embodiment, the amount of water isfrom about 0 to about 15 weight parts per 100 weight parts of the totalcomposition. In one embodiment, the amount of non-volatile mineral acidis from about 0 to about 500 parts per million parts of totalcomposition in weight.

The compound HO—(CH₂)_(m)—Z_(n) can be present at from about 1 wt partcompound: 1 wt part first siloxane resin to about 1 wt part compound:10wt part first siloxane resin.

The temperature for reacting step (ii) is not crucial, provided it is atemperature at which the compound having the formula HO—(CH₂)_(m)—Z_(n)can react with silanol moieties of the first siloxane resin. In oneembodiment, reacting step (ii) can be performed at a temperature fromabout 25° C. to about the boiling temperature of a reaction component(the resin, the compound having the formula HO—(CH₂)_(m)—Z_(n), thesolvent if any, or the water if any, among other compounds whosepresence in the second reaction mixture may be desirable).

The duration of reacting step (ii) is not crucial, provided it issufficiently long for the reaction of the compound having the formulaHO—(CH₂)_(m)—Z_(n) with silanol moieties of the first siloxane resin togo to a desired level of completion. In one embodiment, the duration ofreacting step (ii) can be about 10 min to about 60 min.

Reacting step (ii) can be performed in the presence of a catalyst whichpromotes the reaction between the compound having the formulaHO—(CH₂)_(m)—Z_(n) and silanol moieties of the first siloxane resin. Thecatalyst can be a base or an acid. In one embodiment, reacting step (ii)can be performed in the presence of a mineral acid.

As a result of reacting step (ii), the first siloxane resin issubstituted with an —O—(CH₂)_(m)—Z_(n) moiety. Because this moiety hasdye properties, the product can be referred to as a “dyed siloxaneresin.”

Reacting steps (i) and (ii) can be performed sequentially orsimultaneously. In simultaneous performance, the alkoxysilanes, thewater, and the compound having the formula HO—(CH₂)_(m)—Z_(n) arereacted in the presence of a hydrolysis catalyst to form the dyedsiloxane resin.

In another embodiment, the present invention relates to a method ofpreparing an anti-reflective coating on a substrate, comprising:

coating a composition onto a substrate to form a coated substrate,wherein the composition comprises a siloxane resin having the formula(HSiO_(3/2))_(a)(SiO_(4/2))_(b)(HSiX_(3/2))_(c)(SiX_(4/2))_(d), whereineach X is independently —O—, —OH, or —O—(CH₂)_(m)—Z_(n), provided atleast one X is —O—(CH₂)_(m)—Z_(n), wherein Z_(n), is a polycyclicaromatic hydrocarbon moiety comprising n aromatic rings, wherein each mis independently an integer from 1 to about 5, and each n isindependently an integer from 1 to about 6; 0<a<1, 0<b<1, 0<c<1, 0<d<1,and a+b+c+d=1; and

curing the coated substrate, to form the anti-reflective coating on thesubstrate.

In the coating step, the composition has been described above. Thepresence of —O—(CH₂)_(m)—Z_(n) in the siloxane resin impartsanti-reflective properties to the siloxane resin. The substrate can beany material which it is desirable to coat with the siloxane resin ofthe composition. In one embodiment, the substrate is a semiconductorwafer, such as a silicon wafer. Typically, the wafer can comprise atleast one semiconductive layer and a plurality of other layerscomprising various conductive, semiconductive, or insulating materials.

Coating can be performed by any appropriate technique. In oneembodiment, the coating can be performed by coating. Typically, coatinginvolves spinning the substrate, such as at about 2000 RPM, and addingthe solution to the surface of the spinning substrate.

The coated substrate is cured to form the anti-reflective coating on thesubstrate. Curing generally comprises heating the coated substrate to asufficient temperature for a sufficient duration to lead to curing. Inone embodiment, the coated substrate can be heated at about 50° C. toabout 300° C. for a duration of about 0.1 min to about 60 min. Inanother embodiment, the coated substrate can be heated at about 150° C.to about 275° C. for a duration of about 1 min to about 5 min.

To protect the dyed siloxane resin of the coated composition fromreactions with oxygen or carbon during curing, the curing step can beperformed under an inert atmosphere. An “inert atmosphere,” as usedherein, is a gas or mixture of gases, substantially devoid of gasescontaining oxygen and gases containing carbon. The inert atmosphere cancomprise nitrogen, a noble gas, or a mixture thereof. In one embodiment,the inert atmosphere consists essentially of nitrogen, with othercomponents, if any, being typical contaminants of industrial-grade orresearch-grade nitrogen.

Once cured, the substrate comprising the anti-reflective coating can beused in further substrate processing steps, such as photolithography.

The following examples are included to demonstrate preferred embodimentsof the invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the examples which follow representtechniques discovered by the inventor to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

EXAMPLE 1

Siloxane resin samples 1-1 through 1-11 were prepared by combining in aglass container components (A) 2-ethoxyethanol, (B) 8.4% HCl/H₂Osolution, (C) triethoxysilane, (D) tetraethoxysilane and (E)methyltrimethoxysilane in the amounts described in Table 1. Theresulting solution was heated under reflux for 10 minutes. (F) 10%aqueous sulfuric acid was added according to Table 1. The reactionproduct was stripped of volatiles under reduced pressure at 70° C. untilthe solid content became 2.64%.

TABLE 1 Preparation of siloxane resin samples. Wt Wt Wt Wt Wt Wt partsparts parts parts parts parts Sample Resin type (A) (B) (C) (D) (E) (F)1-1 (HSiO3/2)n 91.07 .74 6.19 0 0 0.75 1-2 (HSiO3/2)0.8(SiO4/ 91.08 2.764.67 1.49 0 0.75 2)0.2 1-3 (HSiO3/2)0.6(SiO4/ 91.11 2.77 3.31 2.80 00.75 2)0.4 1-4 (HSiO3/2)0.4(SiO4/ 91.13 2.79 2.10 3.99 0 0.75 2)0.6 1-5(HSiO3/2)0.2(SiO4/ 91.15 2.80 1.00 5.06 0 0.75 2)0.8 1-6 (SiO4/2)n 91.162.81 0 6.03 0 0.75 1-7 (MeSiO3/2)n 93.77 2.17 0 0 4.06 0.75 1-8 (MeSiO3/93.10 2.33 0 1.54 3.02 0.75 2)0.75(SiO/4 2)0.25 1-9 (MeSiO3/ 92.45 2.490 3.06 2.00 0.75 2)0.5(SiO4/ 2)0.5  1-10 (MeSiO3/ 91.80 2.65 0 4.55 0.990.75 2)0.25(SiO4/ 2)0.75  1-11 (MeSiO3/ 92.58 2.42 2.73 0 2.27 0.752)0.5(HSiO3/ 2)0.5

EXAMPLE 2

Dyed siloxane resin samples 2-1 to 2-6 were prepared by mixing 1.42weight parts of 9-anthracenemethanol, 100 weight parts of a resinsolution and 11.4 weight parts of water according to Table 2 and heatingthe mixtures under reflux for 40 minutes. The products were filteredthrough 0.2 μm filters, spin-coated on silicon wafers at 2000 RPM, curedat 200° C. for 3 minutes in nitrogen using a Rapid Thermal Processor.The cured coatings were tested for optical extinction coefficients usinga Woolam Elliposometer, and tested for HF etch rate by treating thefilms with 0.2% aqueous HF for 2 minutes, rinsing with water and then2-ethoxyethanol solvent, and testing thicknesses before and after etch.The results were summarized in Table 2. Example 2-1 to 2-6 demonstratedthat dyed siloxane resins containing substantially no Si—C bonds in anorganic solvent led to films that can retain their optical propertiesafter thermal cure and have high HF etch rates.

TABLE 2 Preparation and characterization of dyed siloxane resin sampleshaving substantially no Si—C bonds. (K is extinction coefficient). K@248 nm HF Etch ARC Resin Resin precursor Cured at rate Sample precursortype 200° C. Å/min 2-1 1-1 (HSiO3/2)n 0.31 >190 2-2 1-2(HSiO3/2)0.8(SiO4/ 0.29 >190 2)0.2 2-3 1-3 (HSiO3/2)0.6(SiO4/ 0.30 >1902)0.4 2-4 1-4 (HSiO3/2)0.4(SiO4/ 0.29 >190 2)0.6 2-5 1-5(HSiO3/2)0.2(SiO4/ 0.36 >190 2)0.8 2-6 1-6 (SiO4/2)n 0.25 >190

COMPARATIVE EXAMPLE 3

Dyed siloxane resin samples C3-1 to C3-5 were prepared by mixing 1.42weight parts of 9-anthracene-methanol, 100 weight parts of a resinsolution having substantial Si—C bonds shown in Table 3, and 11.4 weightparts of water and heating the mixtures under reflux for 40 minutes. Theproducts were filtered through 0.2 μm filters, spin-coated on siliconwafers at 2000 RPM, and cured at 200° C. for 3 minutes in nitrogen usinga Rapid Thermal Processor. The cured coatings were tested for opticalextinction coefficients using a Woolam Elliposometer and tested for HFetch rates by treating the films with 0.2% aqueous HF for 2 minutes,rinsing with water and then 2-ethoxyethanol solvent, and testingthicknesses before and after etch. The results were summarized in Table3. Comparative Examples C3-1 through C3-5 demonstrated that siloxaneresin-based compositions having large fractions of Si—C bonds led tofilms having low HF etch rates.

TABLE 3 Preparation and characterization of dyed siloxane resin sampleshaving large fractions of Si—C bonds. (K is extinction coefficient). K@248 nm HF Etch ARC Resin Resin precursor Cured at rate Sample precursortype 200° C. Å/min C3-1 1-7 (MeSiO3/2)n 0.18 15 C3-2 1-8(MeSiO3/2)0.75(SiO4/ 0.25 17 2)0.25 C3-3 1-9 (MeSiO3/2)0.5(SiO4/ 0.29 02)0.5 C3-4  1-10 (MeSiO3/2)0.25(SiO4/ 0.24 39 2)0.75 C3-5  1-11(MeSiO3/2)0.5(HSiO3/ 0.20 56 2)0.5

All of the compositions and methods disclosed and claimed herein can bemade and executed without undue experimentation in light of the presentdisclosure. While the compositions and methods of this invention havebeen described in terms of preferred embodiments, it will be apparent tothose of skill in the art that variations may be applied to thecompositions and methods and in the steps or in the sequence of steps ofthe methods described herein without departing from the concept, spiritand scope of the invention. More specifically, it will be apparent thatcertain agents which are chemically related may be substituted for theagents described herein while the same or similar results would beachieved. All such similar substitutes and modifications apparent tothose skilled in the art are deemed to be within the spirit, scope andconcept of the invention as defined by the appended claims.

1. A composition, comprising a siloxane resin having the formula:(HSiO_(3/2))_(a)(SiO_(4/2))_(b)(HSiX_(3/2))_(c)(SiX_(4/2))_(d), whereineach X is independently —O—, —OH, or —O—(CH₂)_(m)—Z_(n), provided atleast one X is —O—(CH₂)_(m)—Z_(n), wherein each m is independently aninteger from 1 to about 5, Z is an aromatic moiety, and each n isindependently an integer from 1 to about 6; 0.3≦a≦0.7, 0.3≦b≦0.7,0<(c+d)≦0.4, and a+b+c+d=1.
 2. The composition of claim 1, wherein eachX is independently —O—, —OH, or —O—(CH₂)—Z₃, provided at least one X is—O—(CH₂)_(m)—Z₃.
 3. The composition of claim 2, wherein —(CH₂)_(m)—Z₃ isa 9-anthracene methylene moiety.
 4. The composition of claim 1, furthercomprising an organic solvent.
 5. The composition of claim 4, whereinthe organic solvent is 2-ethoxyethanol, 1-methoxy-2-propanol, orpropylene glycol monoether.
 6. A method for preparing a dyed siloxaneresin composition according to claim 1, comprising: (i) reacting atrialkoxysilane, a tetraalkoxysilane, and water, in the presence of ahydrolysis catalyst, to form a first siloxane resin having HSiO_(3/2),SiO_(4/2), HSiX′_(3/2), and SiX_(4/2) units, wherein X′ is independently—O— or —OH, and having substantially no silicon-carbon bonds; and (ii)reacting the first siloxane resin with a compound having the formulaHO—(CH₂)_(m)—Z_(n), wherein each m is independently an integer from 1 toabout 5, Z is an aromatic moiety, each n is independently an integerfrom 1 to about 6, 0.3≦a≦0.7, 0.3≦b≦0.7, 0<(c+d)≦0.4, and a+b+c+d =1, toform the dyed siloxane resin composition.
 7. The method of claim 6,wherein the hydrolysis catalyst is a base or an acid.
 8. The method ofclaim 7, wherein the hydrolysis catalyst is a mineral acid.
 9. Themethod of claim 6, wherein reacting step (ii) is performed at atemperature from about 25° C. to about the boiling temperature of areaction component and for a duration of about 10 min to about 60 min.10. The method of claim 6, wherein reacting step (ii) is performed inthe presence of a mineral acid.
 11. The method of claim 6, whereinreacting steps (i) and (ii) are performed simultaneously.
 12. A dyedsiloxane resin composition, prepared by the method of claim
 6. 13. Amethod of preparing an anti-reflective coating on a substrate,comprising: (i) coating a composition onto a substrate to form a coatedsubstrate, wherein the composition comprises a siloxane resin having theformula (HSiO_(3/2))_(a)(SiO_(4/2))_(b)(HSiX_(3/2))_(c)(SiX_(4/2))_(d),wherein each X is independently —O—, —OH, or —O—(CH₂)_(m)—Z_(n),provided at least one X is —O—(CH₂)_(m)—Z_(n), wherein each m isindependently an integer from 1 to about 5, Z is an aromatic moiety, andeach n is independently an integer from 1 to about6; 0.3≦a≦0.7,0.3≦b≦0.7, 0<(c+d)≦0.4, and a+b+c+d =1; and (ii) curing the coatedsubstrate, to form the anti-reflective coating on the substrate.
 14. Themethod of claim 13, wherein the curing step (ii) comprises heating thecoated substrate at about 50° C. to about 300° C. for a duration ofabout 0.1 min to about 60 min.
 15. The method of claim 14, wherein thecuring step (ii) comprises heating the coated substrate at about 150° C.to about 275° C. for a duration of about 1 min to about 5 min.
 16. Themethod of claim 14, wherein the curing step (ii) is performed under aninert atmosphere.
 17. The method of claim 16, wherein the inertatmosphere consists essentially of nitrogen.
 18. A semiconductor wafer,prepared according to the method of claim 13.